Introduction
1N4007 is general silicon rectifier diode with the a plastic package form of DO-41. It is widely used in various AC-to-DC rectifier circuits, and also used in bridge rectifier circuits. 1n4007 utilizes the unidirectional conductivity of diodes to convert alternating current into pulsed direct current in a single direction. So it plays an important role in many circuits.
1 1N4007 Diode Specifications
1.1 Rectifier Diode
1N4007 is a kind of rectifier diodes. In the case of low power, the forward voltage is about 0.6 to 0.8 V. In the case of high power, the forward voltage drop often reaches about 1V. The reverse recovery time is at the us level and can only be used in low-frequency circuits.
Rectifier diodes are the most widely used in electronics. Rectification makes full use of the unidirectional conductivity of the diode. The AC signal is converted into a pulsating DC signal by blocking the negative half cycle of the waveform. It is usually used in combination with a capacitor. The diode is connected in series and the capacitor is connected in parallel. The function of the capacitor is to make the output pulse smoother through charging and discharging, which is closer to DC, and is a filter capacitor. According to needs, it is divided into half-wave rectification and full-wave rectification.
1.2 What is Meant by 1N4007 Diode?
"1"stands for 1 junction.
"N" is the U.S. EIA (Electronic Industries Association) registration mark, and a diode with this letter indicates that it has been registered in the U.S. EIA.
"4007" is the registration number of the device in the U.S. EIA.
1.3 1N4007 Pins and Symbol
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1.4 1N4007 Basic Parameters
Standard Recovery
Strong forward surge bearing capacity: 30A
Maximum forward average rectified current: 1.0A
The limit parameter is VRM≥50V
Maximum reverse withstand voltage: 1000V
Maximum reverse leakage current: 5uA
Forward voltage drop: 0.7V
Maximum reverse peak current: 30uA
Typical thermal resistance: 65°C/W
Typical junction capacitance: 15pF
Working temperature: -50℃～+150℃
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1.5 1N 4007 Feature
·Low reverse leakage current
·Strong forward surge tolerance
·High temperature welding guarantee
·250℃/10 seconds, 0.375" (9.5mm) lead length.
(The lead can withstand 5 pounds (2.3kg) of pulling force.)
·Terminal: Tinned axial lead
·Polarity: The color ring end is cathode
·Installation location: Any
2 1N4001-1N4007 Series Diodes Comparisons
1N4001 (1A, 50V)
1N4002 (1A, 100V)
1N4003 (1A, 200V)
1N4004 (1A, 400V)
1N4005 (1A, 600V)
1N4006 (1A, 800V)
1N4007 (1A,1000V)
3 Alternative Models
1N4007 can be replaced by 1n5408 and 1n5399. If reverse recovery time is not required, FR107 and UF4007 can also be used.
If better performance is required, some supplement tubes can be used instead, such as quick recovery Schottky diodes, which can improve the power supply performance, such as 1SS294, BAT54A, 1N5818, SB540, MBR1645 and so on. These can greatly improve the low frequency response performance of the power supply.
4 1N4007 Application Examples
Example 1
The slow recovery power frequency rectifier tube 1N4007 is used to rectify the power supply winding of the main control IC to solve the problem of high bias voltage in the multi-winding system. Using a certain IC as a 5-way output DVB power supply, during the mass production process, it is found that the defective rate was high, and the symptom is that the power supply doesn’t work or hiccups. After test, it is found that the power supply voltage of the IC is too high, and the IC overvoltage protection mechanism is triggered.
Everyone knows that for a multi-output power supply, to achieve a good cross-regulation rate is quite a test of the transformer design skills, and it is inevitable that the bias supply winding voltage is too high. When multiple sets of power supplies have been mass-produced, redesigning the transformer is obviously not a good solution.
Fig 1. IC Control Circuit
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Also the increase in the resistance of the rectifier diode in series is limited. Because its main function is to filter out the peak voltage, and what causes the IC to protect is the high bias winding voltage. At this time, the charm of the slow rectifier tube is reflected. Change the fast recovery diode HER107 to 1N4007, the problem is solved perfectly. Due to the load is not large, there will be no major problems with the normal use of the circuit.
Example 2
The RCD absorption circuit in Flyback uses the slow tube 1N4007 to solve the leakage inductance peak voltage stress and EMI radiation problems on the main switch. Because if the transformer design is unreasonable and the leakage inductance is large, the leakage inductance voltage will be large when the switch tube is off. And meanwhile, the oscillation time will be longer, resulting in a relatively large MOS voltage stress and excessive EMI radiation.
Fig 2. RCD Absorption Circuit
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With 1N4007, the drain oscillation is perfectly suppressed and the peak value is greatly reduced, thereby reducing the voltage stress of the MOS and greatly improving EMI. The voltage peak of R1 will become larger, because 1N4007 reverse recovery time is longer, so the electricity of C1 will be caused by backflow. Experiments have shown that reducing the loss of R2 will increase the efficiency of the power supply, but the actual measurement has not found an improvement in efficiency, so here we will keep neutral. However, the energy reflux actually exists, and both theoretical analysis and actual measurement results have shown it. That is, the 1N4007 will generate more heat, so this solution is suitable for low-power Flyback, high-power is not recommended. If in the design, the MOS voltage stress is relatively large and the total EMI exceeds the standard, you can also try to use a 1N4007.
Get the full details from 1N4007 Diode Basics Guide.
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